US Patent 10317200 Multi-mode sensor for surface orientation

The present disclosure relates generally to wearable devices and methods for detecting relative surface orientation. The wearable devices and methods may include a multi-mode sensor comprising emitter-detector combinations (e.g., sets or pairs) that have various spacings between the light emitter and the photodetector. Proximity curves can be generated based upon the various emitter-detector pair spacings, and used to assess surface distance and angular orientation of the wearable device to a body surface of an individual. In some variations, location and/or orientation of the device relative to the body surface is determined based on mapping data acquired by one or more emitter-detector pairs to surface distance (z distance) values based on proximity curve data stored in a memory of a device controller.